A lens made of high-refraction low-dispersion optical glass and a lens made of high-refraction high-dispersion optical glass can be combined for chromatic aberration correction and optical system miniaturization. Especially, the market demands on the high-refraction low-dispersion optical glass with refractive index nd of 1.86-1.92 and Abbe number νd of 36-42 are increasing.
JP2001-348244, JP2007-269584 and CN101386469A discloses such high-refraction low-dispersion optical glass, and the optical glass component with the refractive index of more than 1.86 in the embodiments of the Description contains a lot of Ta2O5, while Ta2O5 belongs to an expensive rare earth oxide. Thus, to inhibit the cost of high-refractive index and low-dispersion optical glass material from increasing, it is hopeful to reduce the content of Ta2O5. Meanwhile, the optical element of the optical system for camera shooting or projecting, etc. has higher requirements for the transmittance of optical glass, and the transmission light of the optical system will be affected if the transmission light of the lens formed by high-refraction low-dispersion optical glass is not enough, therefore optical glass is hopeful to have an excellent transmittance.